A Simple Junction for Reference Electrodes Many kinds of junction devices such as cracked glass heads, ashestor libera, ceramicfrits, and agar gel plugs have been used for reference electrodes.' For elertrochemical experiments. one often needs an electrode junction that is small in sine, low in electrical resistance, and law in leak rate. In addition co the above designs, we have found that asatisfactory junction, as s h o w in the figure, can bceasily fabricated by fixing a cylindrical piece uf muleeular sieves to the tip of a glass tubing using a short segment of plastic heat-shrinkable tube. The electrical resistance of such a iunction soaked in 3~ KC1 aqueous solution is about 500 to 1000 Cl. With a 5-em column of electrolvte above the iunction. the rate a t which eleetrolvte leaks is less than 0.002 ,~ m L h The junction material is stable in strong hare, strong oxidizing agents, and organic solvents, but prolonged contact with stnmg acid s h d d be avoided. Hrcause of its amall size, this junction device is particularly useful for mierocells. ~
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'Sawyer, D. T.; Roberts, J. L., Jr. Experimenrol E l r r t r o c h e m i s l ~/or Chemists; Wiley: New York, 1974; p 26. Present address: Altus Corp., 1610 Crane Ct., San Jose. CA 951 12. Shelgon Yee and On-Kok chang2 University of California at Davis Davis. CA 95616
Volume 65
Electrode junction ma& of molecular sieves. A, glass tublng: B, plastlc heatshrinkable tube: C. molecular sieves.
Number 2
February 1988
129
